heartcombo--devise/lib/generators/devise/views_generator.rb

module Devise
  module Generators
    class ViewsGenerator < Rails::Generators::Base
      source_root File.expand_path("../../../../app/views", __FILE__)
      desc "Copies all Devise views to your application."

      argument :scope, :required => false, :default => nil,
                       :desc => "The scope to copy views to"

      class_option :template_engine, :type => :string, :aliases => "-t", :default => "erb",
                                     :desc => "Template engine for the views. Available options are 'erb' and 'haml'."

      def copy_views
        case options[:template_engine].to_s
        when "haml"
          verify_haml_existence
          verify_haml_version
          create_and_copy_haml_views
        else
          directory "devise", "app/views/#{scope || :devise}"
        end
      end

    protected

      def verify_haml_existence
        begin
          require 'haml'
        rescue LoadError
          say "HAML is not installed, or it is not specified in your Gemfile."
          exit
        end
      end

      def verify_haml_version
        unless Haml.version[:major] == 2 and Haml.version[:minor] >= 3 or Haml.version[:major] >= 3
          say "To generate HAML templates, you need to install HAML 2.3 or above."
          exit
        end
      end

      def create_and_copy_haml_views
        require 'tmpdir'
        html_root = "#{self.class.source_root}/devise"

        Dir.mktmpdir("devise-haml.") do |haml_root|
          Dir["#{html_root}/**/*"].each do |path|
            relative_path = path.sub(html_root, "")
            source_path   = (haml_root + relative_path).sub(/erb$/, "haml")

            if File.directory?(path)
              FileUtils.mkdir_p(source_path)
            else
              `html2haml -r #{path} #{source_path}`
            end
          end

          directory haml_root, "app/views/#{scope || :devise}"
        end
      end
    end
  end
end